Preparation of ureas



United States Pate f 2,857,430 PREPARATION OF UREAS Fred Applegath, El-Dorado, Ark., Marion-D. Barnes, Glendale, Mo., and Raymond A. Franz, El Dorado,;

Ark., assignors to Monsanto Chemical Company, St. Louis, Mo a corporationof Delaware.

No Drawing. Application December 31, 1956 Serial No. 631,455

15 Claims. 01. 260-553) This invention relates to urea and substituted ureas and more particularly to an entirely new process for the preparation thereof. 1 i

The so-called carbon dioxide process for makingurea is the only known process which is being operated commercially. Therearea number of modifications to thej carbon dioxide process,- but onlytwo of theseare'now in commercial use. The conditions-vary from 180 C.

and 300 p. s. i. to 210 c. and 6000 p. s. i; and-11pm 250% excess ammonia above thestoichiometric requirement, the yield of urea under these conditions varying from, 40% to 50% per pass. While the carbon dioxide process represents"a 'substantial contribution to the art,,

it "has its drawbacks. One serious drawback is that the cost of constructing and operating the plant is very high' because ofthe highpressure recp 1ired. Another drawback is that the yields "areundesirably low. Still another drawback is diificult. step of recovering ,the

ammonia and carbon-dioxide whichhave not been .con-.

ratentedpcuzl, 1958 2 wherein A represents l a I a R.

represents hydrogen, acyclic, alicyclic and heterocyclic radicals; and B represents angaliphatic group which in conjunction with the nitrogen atom forms a heterocyclic radicalg 4 Theexampless follow' will serve to illustrate thenovel.process of-thiskinvention. These examples are groupednaccordinggto theptype of urea: produced. In

these examples is always: percent by weight. In-

the case of urea, the yield is based on the sulfur charged while in the case of sub'stitutedliureas, the yield is based on the amine charged. The yields of urea were detervetted ,to,-urea., furthermore, the corrosionproblem iS;

least one, and preferably both, of the reactants must be liquefied in order to accelerate the reaction.

An object of this invention is to provide an entirely new and substantially better process for making urea. andfsubstitute'd ureas. Another object is to'provide a. process 1 for making urea and substituted 'ureas'from carbon monoxide, sulfur and either ammonia or an amine or mixtures ,thereof. Other objects will become apparent fromthe description of the invention.

It'has now been discovered that ureas and substituted.

ureas-canbe conveniently and economically, prepared byreacting carbon monoxide, sulfur and a compound selected from the group consistingof ammonia, monoprimary-amines and mixtures of either with secondary amines wherein not more than one. of the substituents attached to the .secondary nitrogen atoznis attached thereto through an aromatic carbon atom. The ureas prepared in accordance with thenovel process of this invention can be represented by the following formula:

mined: I by 1' the: well-known 'Ureasex- "Method. Allowance was made for the. famnioniacal nitrogen; which was deter mined by the formaldehyde method given in A. O. A. C., 7th edition, 1950',-'-p'age' 14, 'paragraph 2.28.

A reaction solution was, prepared I by. mixing together, sulfur, hydrogen sulphide, ammonia and methanol. This solution and carbon; monoxide werexcharged concurrently into the base of'a's'tain less steel packed column 7 tall and-.11: indiarpeten;Areaction-pressure ;of 250p. s; i. g. wasnsed with The reaction solution, acc rdingtothis example, comprised 19.25% sulfur, 24.9% ammonia, 3.52%hydrogen sulfide and 52.3% methyl alcoholnassolvent. This solution was fed to the base of the column above described at,

av rate of .13.? gramsy er minutewitha feed rate of carbon monoxide. of

the top of the column. This solution was evaporated substantially to dryness to removemethanol for re-use and to recover the urea product which was analyzed for urea. u .8- .%,y q d v. 9 -flre .w scb a d- Using-the :sa'me apparatus-and procedure as described inExample'11,"afreaction solutioncomprising 9.37 sulfur, 13.6% ammonia, 3.24% hydrogen sulfide and 73.8%

diethylene glycol as solvent was fed to the base of the column above-described atra rate. of 5 .5 grams per minute,

together with 0.65 gram per minute carbon monoxide. The reactionvwaspontinued for a total of 215 minutes at atemperature .of; -?,C. -No pressure was appliedxto thereactiongsystem othcr thangthe vapor pressure gen.

erated by the reaction mixture: A 7.3.% yield of'urea was obtained. 1 Example 3.Urea

A 1.8 liter stainlesssteel-bomb havingaworking pressure of 400 p. s. i. and provided with a heating element was usedas a reactor. To the reactor werecharged 11.0

gra nsof sulfurjlill'gram of ammonia,L13.0 "grams carbonrnonoxide d1.0 gram hydrogen'sulfide, together with lSO ml; of solventfm'ethanol. The bomb was closed and heated at'ioo" c;-10s' C.'for about 2% hours-with H h ;and --R ;r epresent-hydrogen, acyclic, alicyclic, heterocycl cand.aromatic radicals; R

gramsper minute. Thereaction p h H I tota1;per iodof-186 minutes at a, temperatureofQQ? (11': As indicated, -botha solution of' the urea product and agas,mixture werewithdrawn.from I ence f 150 'ml. *diethyl ethanolamine as r 3 agitation. The bomb was'then tered hot, and the filtrate evaporated substantially to dryness, thereby removing the solvent for re-use and leaving the urea behind as product which was analyzed for urea. An 89% yield of urea was obtained.

Using the same reactor and procedure as described in the preceding example, 11.0 grams of sulfur, 20.0 grams of ammonia, 12.0 grams carbon monoxide and 7.0 grams hydrogen sulfide were charged to the reactor in the pressolvent.j A 91% yield of urea was'obtained.

1 Example 5 .Urea

Using the same reactor and procedure as described in Example 3, 100 grams of'sulfur, 145 grams'of ammonia and-.110 grams carbon monoxide were-charged. to thereactor. 'No solvent or hydrogen sulfide-were used.- 61% yield of urea was-obtained.

GROUP n Ri andRg represent-Hand R, represents acyclic, ali- -Using the same reactor and procedure as described in Example 3, 12.8 grams of sulfur,10.0 grams of ammonia,"

55.5 grams of n-dodecylamine and 14.0 grams of carbon monoxide were charged to the reactor. A.38%' yield of n-dodecylurea was obtained. Y Q f 1 'Examfilje'lfiinflctaelecylurea' 1 Using the same reactor aiidprocedure as described in Example 3, 12.8 grams ofsulfur," 10.0grams of ammonia, 40.5 grams of n-octadecylainine: and l4.0'grams of car- 'bon monoxide werecharged to the reactonf A :87%i' yield of n-octadecylurea was obtained.

Example 9.' Plienylarea 4 Using the same reactor and procedure as fdescribed in Example 3, 13.8 grams of sulfur, 4.0 grams of ammonia, 20.4 grams of aniline and 15.0 grams of carbon monoxide were charged to the reactor. .Phenylureawasrecovered from the reaction mixture. a

Example. 10.Cycl0l1exylurea Using .the same reactor and procedureas described in Example 3," 12.8 grams of sulfur, 10.0 grains of ammonia, 29.7 grams'of cyclohexylamineand 14.0- grams of carbon monoxide are charged'tothe reactor. Cyclohexylurea is obtained.

Example 1 I.-2-lkiasolylarea Using the same reactor and procedure. as described in Example 3, 12.8 grams of sulfur, 10.0 of ammonia, 30.0 grams of 2- aminothiazoleand14. 0'.grams ofv carbon monoxide'jare 'chargedto the reactor. olylu'rea is obtained.

emptied, the contents 151- I i cyclic radical.

' di-substituted areas GROUP R represents H, R represents acyclic, alicyclic, heterocyclic and aromatic radicals and R represents acyclic,

alicyclic and heterocyclic radicals.

Example 12.1,1-dimethylurea,

Using the same reactor and'procedure as described in Example 3, 12.8 gramsof sulfur, 6.8 grams of ammonia, 18.0 grams of dimethylamine and 14.0 grams of carbon.

monoxide are charged to the reactor. 1,1 -dimethylurea'= is recovered.

Example 13.I -methyl-1 -phenylurea Using the same reactor andprocedure as described in Example 3, 12.8 grams of sulfur, 6.8 grams of ammonia,

43.0 grams of N-methylaniline and 14.-0 grams of carbon 1 l-methyl-l-phenylmonoxide are charged to the reactor. urea is recovered.

Ema. 14.-1-eih l -1- -ehzom heaynwear 7 r l Using the samereactor and procedure as described Example 3 12.8 grams of sulfur, 6.8 grams of ammonia,v 62.0 grams of' N-ethyl-p-chloroaniline and 14.0 grams of carbon monoxide are charged to the reactor. (p-chlorophenyl)urea is recovered. j

GROUP l-ethyl-l- R represents H-and B represents an aliphaticwhich in conjunction with the nitrogen atom formsa heterm Example 15. -lV-carbar nylpiperidin1e f Using the same reactor and. procedure astle scribed in Example 3, 12.8 grams of sulfur, 6.8 grams or ammonia}. 34.0 grams of piperidine and 14.0 grams of carbonmonoxide are charged to the reactor.

is recovered.

GROUP 'v. j

R and R, represent acyclic, alicyclic, hetero'cyclic aromatic-radicals and R represents hydrogen Example za -rsaimeth zara- A 11. 8 liter stainless steel bomb having a working pres: surejof'400 p. s. i. and providedwith a heating element, was used asa reactor, The air waspartially removed by evacuating the bomb to a pressure of 30-40 mmIj'Five grams o su1furand1 9.8 grams of gaseous methylamine- ,5, were charged to. the reactor together with 200ml. moth-' Carbon monoxide was then pressured into the reactor until the reactor registered a pressure of anol as solvent.

70p.'s. i. g.[ at room temperature The reactor was then heated for two hours at "C, with'agitation. After 1 this reaction period, the reactor'was" ventedto remove the'by-product H s. The contents were removed as a methanol solution and evaporated to apyglroximately 4;

its original volume and chilled to precipitate theexcess. unreacted sulfur. After filtration, the solution was ,evap-a orated to dryness and the crude .urea product recrystab lized; An 88%, yield, based on amine charged, ,of tlie compound l,3-.dimethylur'eawasobtained.

Y 7' Example. 17

Using the same apparatus and procedure including 200 a ml. methanol as solvent, as described in Example 16 the prepared,

la arnylpip e dine:

{and

listed in Table 1 which follows were i 8 4500 p. s. i. and provided with a heating element and agiof Z-hydroxy-beta-naphthathiazole represented by the fortator, was used as a reactor. The bomb was charged with mula: a 7

64.0 grams of sulfur,'286.0 grams of 'bet -naph h and g ams triethylamine.

No diluent was employed. Carbon monoxide under an initial pressure of 450 pounds was then charged to the bomb. The closed bomb was heated at 120 C. for 4 hours, the reaction mixturebeing agitated during the entire period. The bomb was then vented and rinsed out with methanol. The insoluble urea product was separated by filtration, further extracted (washed) with isoamyl alcohol to remove unreacted amine, and dried. A 19.5% yield, based on the betanaphthylamine charged, of 1,3-bis-(2-naphthy1)urea was obtained. M. P. 288-295 C. M.'P. of authentic material is 290298 C. Mixed M. P. of these was 290 297 C.

Analysis.Percent calculated for C H N Oz N, 9.0. Found: N, 8.33.

The novel process of this invention when applied to this species of the invention results in the production of not only 1,3-bis(2-naphthyl)urea but also a good yield of 2- hydroxy-alpha-naphthathiazole represented by the formula:

enol form keto form Example 24.-1,3-bis(1-mrphthyl) m'ea Using the same apparatus as in Example 23, the bomb was charged with 215.0 grams of alpha-naphthylamine, 96.0 grams sulfur and 16.6 grams triethylamine to provide the initial reaction basicity. Carbon monoxide under an initial pressure of 500 pounds was then charged to the bomb. The closed bomb was heated at 120 C. for 3.5 hours, the reaction mixture'being agitated during the entire period. The bomb was then vented and the reaction product extracted with 15% HCl solution to neutralize excess amine, then with hot ethanol and finally with sodium sulfide solution to extract excess sulfur. The extracted material was then recrystallized from dimethylformamide, giving a 14.3% yield of 1,3-bis(1-naphthyl)- urea. M. P. 289492 C. M. P. of authentic material 296 C., mixed melting point of these was 293294 C.

The novel process 'of-this. invention when applied to this species of the invention results in the production of notbnly1,'3-bis(1-naphthyl)urea but also a good yield keto form enol form 10 This thiazole' can be extracted'from the reaction mixture with acetone. Its melting point was determined to be 299 C.

Example 25 -I ,3-bis(alkylphenyl) urea Using the same apparatus as in Example 23, 260 grams of an alkylaniline, 64 grams of sulfur, and 15ml. of triethylamine were introduced, and an initial carbon mo noxide pressure of 500 lbs. applied. The alkylaniline contained mixed alkyl groups varying from C -C3, with the C alkyl group predominating. The alkyl group was substantially para substituted, although some orthoandmeta-substitution was represented in the mixture. reaction was carried Qut at 115 C. over a period of 4 hours. At the end of the reaction period, the bomb was emptied and the contents treated with a solvent made up of equal parts of ethylene glycol and isopropanol. The insoluble layer, constituting the product urea, was further treated with petroleum ether to separate'traces of unreacted sulfur and alkylaniline. The product urea,

dissolvedin the petroleum ether was heated to evaporate the ether, leaving a viscous, oily product which was iden tified by infrared'analysis. The product was 1,3-bi's(alk'ylphenyl)urea (Alkyl=C -C mostly C groups which were predominantly para substituted).

Ex 'ample 263-1,3-bis(3-chlorophenyl)urea i A one liter Magne-Dashe autoclave, having a working pressure of 4500 p. s. i. and provided with a heatin'g'element and agitator, was used as a reactor. The autoclave 40 was charged with 17.3 grams of sulfur, 34.4 grams of.

3-chloroaniline and 2.7 grams of tn'ethylamineas-a reaction initiator. No diluent was employed. Carbon monoxide under an initial pressure of 250 pounds-was then charged to the autoclave. The closed autoclave was heated at a temperature of 115 C. for 3.5 hours,

the reaction mixture being agitated during the entire period. The autoclave was-then vented and rinsed out with methanol. The urea product-methanol mixture was evaporated to a small volume and dilute HClsolution added to dissolveunreacted amine and precipitate the di-aryl urea product which was recovered by filtration. A 39.6% yield, based on aromatic amine charged, of the compound 1,3-bis(3-chlorophenyl)urea was. obj

The.

tained. M. P. 241-242" C., reported'M. P. 243 C.

TABLE 3a V Base 00 Vol- Reac- Percent Melting Point, O. I Aromatic (tri- Suliur, Presume of tion Temp., Yield Run No. Aromatic Amine Compound Amine, ethyl- Grams sure, Diluent Dil- Time, 0. Based on Grams amin p. s. 1. a. uent, Hours Aromatic Product Litera- Grams m1. Amine 7 ture Ref.

1 2-chloroaniline--; l 3.9 25.1 400 None 0 3. 5 115 29 238-9 235-2336 anilin 34.4 2.7 17.2 250 Methanol. 50 '5 115 65.2 270 2510' 2.3 14.7 200 do. 50 3.5 115 92 50 3.1 19.4' 300 None 0 3.5 115 12 25 72.0 11. 7 200 410 0 V 3. 5 p 115 34. 3 35 3 19 300 do I p 0 1 3. 5 115 31. 7 10 1 5.2 Pyridine" 50 3. 5 -62. 6 28.9 3.6 17.2 250 MethanoL 1 50 I 5 115 p 79.4 20 1. 7 10. 5 200 50 3. 5 115 22. 6 20 1.7 10.5 200 50 3.5 115 40.6 20 1. 7 10. 5 200 1 0- 50 3. 5 115 7. 7 aniline 50 7.2 34. 4 500 None 0. 3. 5 115 86. 2 2 methyl-5-chloroaniline 50 s 4.0 22. 7 400 do. 0 3. 5 115 25. 1 2-methoxy-5-chloroaniline 16 1.0 6.5 200 0 0 3.5{ 115' 6. 3 15 4-anisidine 50 4.0 26.0 400 (in 0 3.5 115 67.2 in (in 50 None 26.0 400 -do 0 3.5 115 37. 5 17 NV-diethyl-p-phenylene- 37.0 None 14. 1 500 -do 0 4 27 e. 18 N,N-dimethy1-p-phenylene- 10.0 None 4.7 500 .do---.- 0 4- 120 B diamine. v r

TABLEl;

Sulfur Amine Duration Percent Temp., Run N 0. Aliphatic Amine Grams Grams, Pressure of Run Yield 0. Product 7 r Hours ethylamine 5. 0 14. 4 60 2 75 115 1,3-diethylurea. n-propylamine 10.0 18.9 g 77 2 71 120 1,3-di-n-propylurea. isopropylamina. 10.0 17.1 73 2 51 120 1,3-di-isopropy1urea. n-butylamine. 10. 0 23. 4 70 2 81 120 1,3-di-n-butylurea. isobutylamine. 10. 0 23. 4 70 2 80 120 1,3-di-isobutylurea. sec-butylamine 10.0 23.0 70 2 71 120 1,3-di-sec-butylurea. tert-butylamine 10.0 23.4 70 2 54 120 1,3-di-tert-butylurea. n amylamine. 5. 0 27. 7 70 2 61 120 1,3-di-n-amylurea. n-hexylamine. 5. 0 32. 3 70 2 71 120 1,3-di-n-hexylurea. n-octylamine v 2.5 j 207 54 2 84 120 1,3-di-n-octylurea. tert-octylamine..- 5. 0 42. 0 70 2 29 120 1,3-di-tert-0ctylurea. n-decylarnine 2.5 25.2 70 2 70 120"l,3-di-n-deeylurea. n-dodecylamm 2. 6 29.4 70 2 80 120 1,3-di-n-dodeeylure'a. v n-tetradecylamin 10. 0 34. 0 70 1% 61 120 1,3-di-n-tetradeeylurea. n-octadecylamme 1. 3 21. 53 2 71 120 l,3-di-n-octadeeylurea. allylamine 5.0 17.8 70 2 78 120 1 -di-allylurea. methallylamme 5.0 22.8 70 2 54 '120 1,3-dimethallylurea.

a-methylbenzylamine 2.7 1 20.0 70 37 120 1,3-bis(a-methylbenzyl)urea. benzylamine 10. 0 34. 3 73 2 62 120 1,3-dibenzylurea. cyclohexylamine 10. 0 .22. 7 50 2 63 120 1,3-dicyclohexylurea.

1 The reaction time was minutes. I] Example 18.1,3-bzs(5-carboxyamyl) urea Example 21 .1,3-b1s(Z-N-morpholznoethyl) urea A 1.8 liter stainless steel bomb, having a Working 25 Using the same equipment set forth in Example 18,

pressure of 400 p. s. i. and provided with a heating element, was used as a reactor. The bomb was charged with 1.2 grams of surfur, 10 grams of'e-amiuocaproic acid'and 200 ml. of methanol as diluent. Carbon monoxide was charged to the reactor under an initial pressure of 70 p. .s. i. a. The closed bomb was heated at about 120 C. for 2 hours with agitation. Thereactor was then emptied and the contents filtered hot. The'filtrate was evaporated to dryness on a steam bathleaving behind a crude product containing unreacted amine. The crude product was dissolved in dilute NaOH solution, and acidified with HCl and chilled to precipitate the substituted urea from the thus formed amine hydrochloride solution. Based on'the amine charged, a 52% yield of the.compound 1,3-bis(5- carboxylamyDurea was obtained;v M. P. l52-155 C.

Anglysis.Percent calculated for C I-1 4N 0 C,

53.96; H, 8.36; N, 9.68; Found: C, 54.01; H, 8.44; N,

Example 19.+1,3-bis(3-hydroxypropyl) ur ea Using the equipment set forth in Example 18, 3.2 grams of sulfur; 15.0 grams of 3-hydroxypropylamine, 50 ml of methanol as diluent, and carbon monoxide. at an initial pressure of 70 p. s. i. a. were charged to the reactor. The closed bomb was heated at about 120 C. for 2 hours with agitation. The reactor was then emptied and the contents filtered hot. The filtrate was evaporated to a smaller volume and cooled to crystallize out the substituted urea product. Based on the amine charged, a 74% yield of the compound 1,3-bis(3-hydroxypropyl)urea was obtained, M. P. above 80 C.

Analysis.Percent calculated for C H N O N, 15.9.

. Found: N, 16.51.

Example 20.1,3-bis(2-cyan0ethyl) urea Using the same equipment setforthin Example 18, 3.4 grams of sulfur, 15.0 grams of B-cyanoethylamine, 200 ml. of methanol as diluent, and carbon monoxide at an initial pressure .of 80 p. s. i. a. were charged to the reactor. The closed bomb was heated at'about 100 C. for 2 hours with agitation. The reactor was then emptied and the contents filtered hot. The filtrate was evaporated to a smaller volume and cooled to separate out the crude substituted urea product. The crude product Was dissolved in methanol, treated with activated charcoal to remove color, and then recrystallized from the methanol to yield a yellow crystalline material, M. P. 144-146? C. Based on the amine charged, a 32% yield of the 'compound 1,3-bis(2-cyanoethyl)urea was obtained.

Analysis.Percent calculated for C- H N O C, 50.59; H,-6.07;-N, 33.72; Found: C;49:47'; H, 5.55; N, 34:25;

4.9 grams of sulfur, 20 grams of N-(2-aminoethyl)- morpholine, 200 ml. methanol as diluent, and carbon monoxide at an initial pressure of 70 p. s. i. a. were charged to the reactor. The closed bomb was heated at about 120 C. for 2 hours with agitation. The reactor was then emptied and the contents filtered hot. The

filtrate was'evaporated to dryness, leaving behind a dark 1 oil as product. The oil was dissolved in benzene, treated with activated charcoal to remove color, and then recrystallized from the benzene to yield a crystalline product, M. P. 104-106" C. Based on the amine charged, a 60.2% yield of the compound 1,3-bis(2-N-morpholinoethyl)urea was obtained.

Analysis.Percent calculated for C H N4O C, 54.52; H, 9.15; N, 19.56. Found: C, 54.39; H, 8.69; N, 19.01. 0

Example 22 .1,3- difurfmylllrea Using the same equipment set forth in Example 18,-

5.0 grams of sulfur, 10 grams of furfurylamine, ml.- of methanol as diluent, and carbon monoxide at an initial pressure of 75 p. s. i. a. were charged to the reactor. The closed bomb was heated atabout C. for 2 hours with agitation. The reactor was then emptied and the contents filtered hot. The filtrate was evaporated substantially to dryness, leaving behind crude product.

The crude productwas recrystallized from water to yield a crystalline material, M. P. 126-129 C. Based on the amine charged, a 73.0% yield of the compound 1,3-difurfurylurea was obtained.

Analysis.-Percent calculated for C H N O N, 12.7.

Table 2 which follows lists a number of bis-aliphatic substituted ureas which may be prepared according to'ou'r process in addition to those prepared as set forth in the preceding Table 1 and examples. These further com pounds are not intended to encompass a listing. of all the ureas of this type which can be prepared, but are presented only.

for illustrative purposes TABLE 2 Reaetant Amine Product 3-isopropoxypropylamine S-methoxypropylamine... p-methoxybenzylamine til-alanine. N -acetoethylene diamin l,3 -bis (3-methoxypropyl) urea. 1,3-bis( -metho'xybenzyl) urea. 1,3-bis(2-carboxyethyl)nrea. 1,3-bis (Z-acetamidoethyl) urea.

Example 23 .-1 ,3-bis(2-naphthyl) urea A- two" liter Parr bomb, having'a working pressure" of 1,3-bis(3-isopropoxypropyl)urea.

TABLE 3b Run No.

2-chlor0aniline 4-chloroaniline 4-aminophen0l t ethyl-4-aminobenz 1,3-bis(2-ch.lorophenyl)urea. 1,3-bis(4-cblorophenyl)urea. 1,3rbis(4-hydroxyphenyl)urea. 1,3 bis(4 carbethoxyphenyD- urea.

5 4-aminobenzoic acid 1,3-bis(4-carboxyphenyl)urea.

6 4-aminobeuzonitrfle. 1,3-bis(4cyanophenyl)urea.

7 4-anisid' 1,3-bis(Mnethoxyphenyburea.

8 4-toluidine. 1,3-bis (4-methylphenyl) urea.

9 2,4-dimethyl 1, 3 bis(2,4 dimcthylphcnyhurea.

10 2,5-dimethylaniline 1,3 bis(2,5 dimetl1ylphenyl)- urea.

11 2,6-dimethy1am'line 1,3 bis(2,6 dimethylphenyD- urea.

12--- aniline 1,3-diphenylurea.

13 Z-methyl-fi-chloroaniline 1,3 bis(2 methyl 5 chloro phenyDurea.

14 2-meth0xy-5-chloroaniline 1,3 bis(2 methoxy 5 chloro phenyDurea.

15--- i-anisidiue 1,3-bis(4-methoxyphenyburca.

16 do D0.

17 N,N diethyl p phenyl 1,3 bis(4 dicthylaminophenenediamine. urea. 18 'N,N-dimethyl p phenyl 1,3-bis(4rdimethylaminophcnenediamine. yl)urea.

clave, in which case the urea product was recovered by simple filtration.

Example 27.1-ethyl-3-methylurea Using the same reactor and procedure as described in Example 26, 8.0 grams of sulfur, 7.8 grams of methylamine, 11.2 grams of ethylamine and 8.4 grams of carbon monoxide are charged to the reactor. 1-ethyl-3-methylurea is recovered.

Example 28.1-cycl0hexyl-3-phenylurea Using the same reactor and procedure as described in Example 26, 16.0 grams of sulfur, 19.8 grams of cyclohexylamine, 23.2 grams of aniline-and8.4 grams of carbon monoxide are charged to the reactor. 1-cyclohexyl-3- phenylurea is recovered.

GROUP VI R and R represent acyclic, ali cyclic, heterocyclic and aromatic radicals and R represents acyclic, alicyclic and heterocyclic radicals.

Example 29.--I,1-dimethyl-3-phenylurea A 1.8 liter stainless steel bomb, having a Working pressure of 400 p. s. i. a. and provided with a heating element, was used as a reactor. The bomb was charged with 13.8 grams of sulfur, 20.0 grams of aniline, and 29.0 grams of dimethylamine. Methanol was added as a diluent, 77 ml. being used. Carbon monoxide was charged to the reactor under an initial pressure of 100 p. s. i. The closed bomb was heated at about 100 C. for approximately 2 hours with agitation. The reactor was then emptied and the contents filtered hot;- The filtrate was evaporated to a small volume, leaving behind a slurry containing crude substituted urea. The crude slurry was mixed with 400 0 ml. hot water to dissolve unreacted amine and the substituted urea. This solution was then chilled to precipitate. the substituted urea which was then recovered by filtration. Based on the primary amine, a yield of. 79.0% of 1,1-dimethyl-3-phenylurea was obtained; M. P. found: 131-133 0.; reported M. P.: 134 C.

Example 30.1-(4-carb0xyphenyl)r3,3dimethylurea Using the same equipment and procedure set-forth in Example 29, 10.0 grams of 4-arninobenzoic acid, and 9.9 grams of dimethylamine were charged tothe reactor after introducing 4.7 grams of sulfur." Thirty-three ml.. .of' methanol was used as diluent, and carbon monoxide at an initial pressure of p. s.-i. a. was introduced. Reac- Example 31 .1,1-dimethyl-3-(4-liydroxyphenyl) urea Using a 2 liter stainless steel Parr bomb equipped with a heater and agitator, 55.0 grams of 4-aminophenol, and 73.0 grams of dimethylamine were charged to the reactor together with 32.0 grams of sulfur, carbon monoxide at an initial pressure of500 p. s. i. a., and 300 ml. of methanol as diluent. After 2 hours reaction time at 100 C. with agitation, the reaction mixture was removed from the bomb and evaporated to a paste. The paste was slurried with 200 ml. toluene, filtered, washed with 6070 C. hexane and dried. 'A 63.7% yield of 1,1- dimethyl-3-(4-hydroxyphenyl)urea was obtained having a melting point of 195-197 C. The product was a light, cream colored, long needled crystalline solid.

Example 32.1,1-dimethyl 3- (4-a'imethylamin0- phenyl) urea Proceeding as in Example 29, 4.7 grams of sulfur, 9.9 grams of dimethylamine, and 10.0 grams of 4-N-dimethylaminoaniline, and carbon monoxide at 100 p. s. i. a.

initial pressure were mixed with 26 ml; of methanol as Example 33 .-1 -(4 carlaethoxyphenyl)-3,3-dimethylurea The compound of 1.-(4-carbethoxyphenyl)-3,3-dimethylurea was prepared according to the procedure of Example 30. Forty'grams of ethyl=4-aminobenzoate, 34.4 grams of dimethylamine, 15.5 gramsof sulfur and carbon monoxide'under an initial pressure of p. s. i. a.'were mixed with 50ml. of ethanol as' diluent. The reaction was carried outwith agitation-for Zhours at 100 C. The urea was separated from :the reaction mixture as described, with a yield of 35.4% based on primary amine being obtainedgM. P. 144146 C.

Analysis.-Percent calculated for C H O N C, 60.90 g H, 6.82; N, 11.84. Found: C, 60.96; H, 6.87; N, 11.43; I I

Table 4 which follows listsprocess data fora number of additionalu'reas prepared'in a manner similar to that described in the precedingexamplest 7 TABLE 4 1" l rii. f Sec. C Volume-Yield Product, Product, Sec.'A.mine .I Amine, Amine, Sulfur, Pres- Diluent Dllu- Based M. P., B. P.,-

. Grams Grams Grams sure, ent, on Fri. C. 0.

' Q p.s.i.a ml v Amine 4101111111118 dimethylamine 22.9 29.0 13.8 100 methanol" 77 54.0 149-152 '4-ch1o'roa1nilii do i 27.3 29.0 13.8 100 77 85.5 169171 4-anisidine 13.2 14.5 6.9 100 d0-.. 40 87.5 130-131 14.4 10.0 7.4 115 none 0 91.5 69-73 27.4 29.0 13.8 100 methanoL. 77 22.7 104-106 7 3-chloro nili V 27.4 29.0 13.8 100 do 77 56.6 144-146 l-napht y 30.8 29.0 13.8 100 dO 77 v 77.5 164 -166 2-naphthylaminero 30.8 29.0 13.8 100 d0- 77 92.0 203-204 3,4-djchloroanilina 347 33.0 13.7 125 do 77 62.0 153-154 aniline 7. 5 14. 0 1. 85 100 benzene.-- 55. 0, 174-176 2-5 dimethoxyaniliu 16.5 14.5 6.9 100 methanoL. 23.0 ,50-53 z-methoxy-5-chloroaniline 30.5 26.1 12.5 110 d0 17.5 63-66 aniline; 7.4 25.0 5.0 fin 50 50.0 156-159 2,4-dimethylanilinek 20.0 22.4 16.0 200 15 81.3 133-136 2,5-dimethylani1ine 20.0 22.4 16.0 200 do 15 68.4 2 fi-dimethylaniline 1 20.0 22. '4 16. 0 200 15 40. 0 133-134 4-ch1oroaniline 10.0 25.0 5.0 100 do 50 66.0 196-200 D0 32.3 24.0 16.0 500 ...do 300 17.3 73-74 methylamine t j V) 31 45 32 650 200 6 2323@760 isobutylaminefl diethylamine .1 14.6 29.2 6.4 215 do 200 12 -8 8 ethylamine 2 di'n-blltylaminei; 17.5 48.5 12.8 110 300 26 128-31 5 1 mm. n-hexylamine V diethy 20. 2 29.2 6. 215 do 200 13 l35-40@ 10 fi-aminopropionic acid di-n-butylamine 10 29 7.2 do 25 36 85 n-hutylamine di-isobutylamine 11 38.7 4.8 215 do 200 13 130-5 13 mm. cyclohexylamine =di-11-propy1am1ne: 20 40.9 12.9 140 none 0 87 82.4 n-hexy1amine=; i 20.2 40.4 6.4 215 methanol; 200 11 130516003 mm. n-butylarnine-.'- d1-n-butylamine 22 39 16 140 .do 300 27 140150@5 n-hexylamine di-isobutylamine- 22.2 51.6 6.4 215 .do 200 '11 11020@13 n-oetylalnine (in 12.9 51.6 6.4 215 do 200 18 125-30@13 mm. n-hexylamine dibenzylamine 10.1 39.4 3.2 215. do 200 15 -2 @12 Norm-Reaction time was 2 hours in each run. Reaction temperature was 100 0. unless otherwise noted.

1 Reaction temperature was 115 C. 2 Reaction temperature was 120 C.

As is to be seen from the preceding examples the novel process of this invention is subject to wide application.

Our study indicates that the stoichiometry of the reaction involved is according to the equation:

zit-NH. 00 s RHN-tfi-NHR H2s cording to the process of this invention.

7 Aspreviously mentioned, the reactlon 1s carried out by reacting carbon monoxide and sulfur withammonia or a mono-primary-amine or mixtures of either with a secondary amine. By mono-primary-amine is meant a compound containing only one reactive -NH group but permitting the presence of other substituent groups which are not deleteriouslyreactive under the conditions of'this reaction.

The mono-primary-amine which can be employed in the practice of this invention .may be described in more detail. by the general formula 'R -NH- wherein R is selected from the group consisting of acyclic, alicyclic, heterocyclic and aromatic radicals. Such radicals include alkyl, aryl (both phenyl and naphthyl), cycloalkyl, a1-

" kenyl, 5 -membered and G-membered heterocyclic radicals having at least one atom in the ring selected from oxygen, sulfur and nitrogen- Such radicals as these can be unsubstitutedor substituted with one or more substituent groups which are not deleteriously reactive under the conditions of this reaction. By the expression groups which arenot deleteriouslyreactive under the conditions of this reaction is meant, groups which do not prevent the formation of any ofthe desired ureap Such substituent groups include alkyl, aryl, cycloalkyl, alkenyl,

carboxy, hydroxy, thiol, .cyano, nitro, halogenincluding chlorine, bromine, fluorineand iodine, alkoxy, aryloxy,

organosi1yl,;.polysiloxanyl; alkylamin'o, dialkylamino,i.etct The position of the substituent groups with respectto.

the amino group in the radical to which. they are attached has some effect on the reactivity of the mono-primaryamine. .Substituent groups either a or ortho to the primary amino group reduce but do not completely prevent thereactivity of the amine to form the ureas of this 111-. In certain instances, a competitive reaction. takes place and it is possible to obtain not only the ureas.

vention.

"I- GO 14 andrecover from"the'urea product, e. g. by evaporation, and they are solvents for many of the amines. Aromatic and aliphatic hydrocarbons, chlorinated hydrocarbons, ethers, tertiary amines and'acid' amides are also suitable.

Water per se is not a satisfactory diluent although small amounts of water in the organic diluent can be tolerated. f secondary amine which can be employed in the Where a diluent is employed, an amount sufficlent to practice of this invention may be described in more'detail slurry the reactants usually P Is by e general formulas ferred, but;not necessary, tohave'a diluent m which the 7 R5 reactants are soluble. In preparing ureas of the class described, the use of excessively. large amounts of solvent HN V should be avoided. I

3 Although not intended tobe li'mitauve, 1n addltion to or HN=Ywherein R represents acyclic, alicyclic, heteromethanol, the following solvents or diluents have been cyclic and aromatic radicals; R represents acyclic, alisuccessfully employed in carrying out the process: l groin, cyclic and hetero-cyclic radicals; and Y represents an P P L P QPY q ethanol, mlnefal 011, aliphatic group which in conjunction with the nitrogen chlofocthylene, trlethylamme, Py lsopl'opaflolatom forms a heterocyclic radical. Such radicals include Watts? ethylene g y c yl p Q fi y f alkyl, aryl (both phenyl and naphthyl), cycloalkyl, alfuryl alcohol, N,N-d1methylan1l1ne, dlethyl ethanolamlne, kenyL'S-membered and 6-membered heterocyclic radicals 0 m myl 0 10 {1nd nze having at least one atom in the ring selected from oxygen, In p p g urea accordmg-to thepresent mventwn. 1t sulfur and nitrogen. Such radicals as these can be un- 18 p ef rred, but not necessary to-employ a small amount substituted or substituted with one or more substituent of y g Sulfide 0 solubllfzlng the Sulfur groups which are not deleteriously reactive under the con- Where a S01Ve 11t 1S p y din the react1on. 'In the case ditions of the reaction. By the expression groups which 5 f the Substltllted Q hOWeVeI, hydrogen Sulfide v1S are not deleteriously reactive under the conditions of the not necessary nor particularly desirable. reaction is meant groups which do not prevent the for- In preparing urea according to the present-invention, a mation of any of the desired urea. Such substituent solution is prepared by mixing together sulfur, hydrogen groups include alkyl, aryl, cycloalkyl, alkenyl, carboxy, sulfide, ammonia and methanol. ThlS solution may' be hydroxy, thiol, cyano, nitro, halogen including chlorine, Prepared in situ in a closed reaction vessel to which bromine, fluorine and iodine, alkoxy, aryloxy, organocarbon monoxide is-charged, or thesolution may be fed silyl, polysiloxanyl, alkylarnino, dialkylamino, etc. into the base of a packedcolumn concurrently with carbon The preparation of urea by the reaction of carbon monoxide. The product urea is recovered from the remonoxide, sulfur and ammonia, the preparation of symaction mixture byany well-known method and the solmetrical disubstituted ureas by the reaction of carbon 3 vent recovered'for re-use. monoxide, sulfur and a mono-primary-amine as above If desired the ammonia and hydrogen sulfide released described and the preparation of trisubstituted ureas by from the reactor and from the methanol distillation can. the reaction of carbon monoxide, sulfur and a mixture of be recovered. Although any suitable means may be ema secondary aliphatic amine and an aromatic mono-priployed, sulfuric acid may be used to absorb the ammary-amine constitute preferred embodiments of this in- 40 monia as ammonium sulfate, with the sulfur value from vention. In these reactions, the use of mono-primary the hydrogen sulfide being recovered by Well-known alkylamines containing from 1 to 18 carbon atoms, partial oxidation methods. mono-primary phenylamines and mono-primary naphthyl- The substituted ureas can be similarly prepared with amines are particularly preferred. In the case of secthe appropriate amine being'substituted for the ammonia. ondary amines, dialkylamines, dialkenylamines and In general the novel process of this invention requires heterocyclic six-membered secondary amines wherein the no added catalyst. The reaction proceeds in an alkaline amino nitrogen forms part of the ring structure are premedium and inmost cases the amines employed provide ferred. sufficient alkalinity. In the case of the aryl substituted Although not essential, 1t 1s desirable in most cases to ureas, an alkaline catalyst, although not absolutely recarry out the process in the presence of an inert solvent quired, has been employed to advantage. This can be or diluent. Aliphatic alcohols, particularly methanol,.are illustrated by a series of runs made using the sarhepropreferred for th1s purpose as they are easy to separate cedure and conditions disclosed in Example 26.

TABLE 5 7 Percent R1111 Aniline, Base, Sulfur, (JO Dil- Time, Temp., Yield Dissoci- No. Grams Basic Additive Grams Grams Pressure, Diluent uent, Hours 0. Based ation p. s. i. a. m]. on Ani- Constant line 20.4 N,N-diethylani1ine e 3.3 14.1 4 120 15 saxro- 20.4 N,N-diethylp-toluidine- 3.6 14.1 4 120 34 1.2 10 20.4 triethanolaminc 3.3 V 14.1 4 120 36 5.9 10- 20.4 N,N-dimethylbenzy1amine 3.0 13.8 4 120 26 8.5)(10- 50 triethylamine ,7.2 34.4 3.5 50 tributylaminm. 10.0 34.4 5 115 50 potassium by 3.0 34.4 5 115 50 sodium hydroxide 2.4 34.4 5 115 50 tetraethylammonium hydroxid 7.9 34.4 5 115 20.4 calcium methylata 2.2 14.1 4 20.4 N,N-dimethyloctadecylamine- 6.6 14.1 4 120 20.4 tri-n-hexylamine. 3.0 14.1 4 120 20.4 magncsium-methylate. 1.6 14.1 4 120 20.4 potash sulfurated 5.9 14.1 4 120 20.4 sodium 0leate 6.6 14.1 4 120 triethylamine 7. 2 34. 4 3. 5 115 0. 72 344 3.5 115 0.36 34.4 500 do 3.5 115 0.18 34.4 500 .do 3.5 115 0.0 34. 600 Methanol. 50 5 115 absolutely necessary.

The reaction was carried out inthe presence of a number of different alkaline materials as additives. The urea prepared was 1,3-diphenyl urea. The results obtained and details of the conditions used are given in Table 5. :Runs 14 and 10-15 were carried out in a 440 ml. .mild steel bomb, whereas the remaining runs were carried out in a 1 liter Magne-Dashe bomb.

It will be observed that the highest yields are obtained, using aniline as the reactant aromatic amine, with the addition of a tertiary amine having a basicity correspondingto the'dissociation constant of triethylamine. The yields drop with the use of tertiary amines of low basicity. Alkaline catalysts having dissociation constants greater than 1X10- are preferred. It is to be noted, however, that while in the preparation of this type of urea, an alkaline catalyst is desirable, it is not In theabsence of added alkaline catalysts of the type discussed herein, the reaction still proceeds but with lower yields.

Strong and weak inorganic bases appear to initiate the reaction about equally as well, although the resulting yields of the ureaare inferior to the preferred tertiary amine. 'Inorganic hydroxides, alkaline inorganic and organic salts andtertiary' aliphatic amines are useful'as catalysts.- Tertiary alkylamines are 'preferred.

As previously indicated the amount of catalyst'to be added to assist ininitiatingthe reaction will vary depending upon the compound selected., In the case of triethylamine, as little as 0.36 gram for '50 grams of reactant aromatic amine'was-found suflicient to render a fairly'good yield of urea. =-A'mounts much below this ratio produced inconsistent results.

The quantifies of reactants used in this process can be *varied substantially without departing from the scope of the invention. In general at least stoichiometn'c proportions of reactants should be used, that is a molar ratio of aminezs'ulfuncarbon monoxide of 'at least 221:1. Excessive quantities of any of the reactants can be used-as desired. The process has been found to be particularly operable using molar ratios of amine to sulfur ranging from-0.1:l .to 8:1. Even higher ratios have been used with good results. Generally the particular ratio of reactants will. be dictated more by economic' considerations than by reactivity considerations. The preceding comments have been concerned with the total molar quantity of amine in the reaction mixture With'reference to the sulfur present. When mixtures of primary and secondary amines are used to produce trisubstituted ureas it has been found advantageous to employ the secondary amine in an amount in excess of the stoichiometric proportion in order to prevent the reaction of the primaryamine from dominating. Thus when such mixtures are used a mol ratio of secondary amine to primary amine of at least 3:1 is preferred, although a mol ratio of secondary amine to primary amine in the range of from 0.5:1 to 8:1, or even higher, is applicable. The quantity of carbon monoxide used in the process can be varied substantially with it being employed in excess of the stoichiometric proportion and the excess being governed primarily by the pressure desired.

The process of this invention is operable over an exceptionally wide pressure range. It can be operated at atmospheric pressure although the reaction proceeds much more rapidly at elevated pressures. Generally pressures from about 30 p. s. i. a. (pounds. per square inchabsolute) to about 1500 p. s. i. a. are applicable.

Higher pressures can be used, if desired, but ofier no advantage. The preferred pressure will vary with the type of urea produced. .In the case of urea and alkyl substituted ureas, pressures rangingfrom 150 p. s. i. a. to 250 p. s. i. a. are preferred. In the case of diaryl substituted ureas, pressures from 36 p. s. i. a. to about 600 p. s. i.a. are preferred. In the case of trisubstituted ureas, pressures ranging from 50 p1 s.'i a. to about 1100 1.6 p. s. i. a. have been found to be particularly applicable. In any event, thepressure is not a critical factor.

The process of this invention can be carried outover a wide temperature range. It is preferably carried out 1' at an elevated temperature. Temperatures ranging from about 60 to about 300 C. have been found applicable.

Generally, reaction temperatures in the range from about 60 C. to about 160 C. are preferred being varied slight: ly depending upon the urea produced. In the case of urea and alkyl substituted ureas, a reaction temperature in the range from about 60 to about 160 C. is preferred. In the case of aryl substituted ureas, a reaction temperature ranging from 115 to 130 C. is preferred. Trisubstituted ureas are preferably produced using a' reaction temperature rangingfrom about 85 to about 160 C.

This application is a continuation-in-part of copenda in'g application Serial No. 547,565 filed November; 17, 1955, now abandoned, copending application Serial No, 553,708 filed December 19, 1955, now abandoned,-and. v copending application Serial No. 594,375 filed-June 28, 1956, now abandoned. The last mentioned application .was a continuation-in-part of application Serial No.

. primary-amine is 3-hydroxypropylamine.

437,882 filed June 18, 1954, now abandoned, and application Serial No. 553,724 filed December 19, 1955, now abandoned. The process of preparing azoles disclosed herein is disclosed and claimed in copending application Serial No. 630,058 filed December 24, 1 956, and Serial No. 646,582 filed March 18, 1957, which were com tinuations-in-part of application. Serial No. 593,040 filed June 22, 1956, now abandoned.

What is claimed:

1. A process for preparing ureas which comprises re acting by mixing at :an elevated temperature carbon monoxide, sulfur and a compound selected from the group.

consisting of ammonia, mono-primary-amines and .mix-

tures of either. with'secondary amines wherein no more 1 than one of the substituents attached to the secondary. nitrogen atom is attached thereto through an aromatic 1 carbon atom.

2. The process as described in claim 1 wherein action is carried out at a temperature in the range of from about 60 to about 300 C.

3. A process for the preparatlon of urea which cornf prises reacting carbon monoxide, sulfur and ammonialat an elevated temperature. i 1

4. A process as described in claim 3 whereln thereaction is carried out at a temperature in the range offrom 6. A process which comprises reacting by mixing i bon monoxide, sulfurand a mono-prrmary-amme ,atan

elevated temperature.

7. A process as described in claim 6 wherein the monoprimary-amine is a mono-pnmary-alkylamine.

8. A process as described in claim 6 wherein the'mono 9. A process which comprises react ng by bon monoxide, sulfur and a mono-primary-arylamine at.

an elevated temperature.

10. A process as described in claim 9 wherein reaction is carried out in the presence of an alkaline jcatalyst having a dissociation constant greater than.

1x10- V D,

11. A process as described in claim 10 wherein the mono-primary-arylamine is aniline.

3 1-2. A process as described in claim 10 wherein the 1 mono-primary-arylamine is naphthylamine.

13. A process for the preparation of substituted ureas. which comprises reacting by mixing'at an elevated tem perature carbon mono 'de, sulfur and a mixture of a mono-primary-amine and a secondary amine wherein no more than one of the substituents attached to the Secondary nitrogen atom is attached thereto through an matic carbon atom.

14. A process as described in claim 13 wherein the References Cited in the file of this patent mono-primary-amine is a. mono-primary-arylamine and the secondary amine is a dialkylamine. Hagelloch: Berichte Chemische Gesellschaft, vol. 83,

15. A process as described in claim 14 wherein the pages 258 to 261 (1953). dialkylamjne is dimethylamine and the mono-primary- 5 Lewis et-aL: I. Am. Chem. Soc., vol. 37, 1915, page arylamine is chloroaniline. 1977.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2Q85TY43O I October 21 1958 Fred Appleg'ath et al.

It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said; Letters Patent should read as corrected below.

Column 5 line .28 for "surfur" read sulfur column 7, line 17 the formula should appear as. shown below instead of as in the patent:

C I-I N2OZ N 9 .0.

columns 11 and 12 TABLE 4 third column thereof eighteenth item for "3263" read 3200 a,

Signed and sealed this 23rd day of August 1960,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

1. A PROCESS FOR PREPARING UREAS WHICH COMPRISES REACTING BY MIXING AT AN ELEVATED TEMPERATURE CARBON MONOXIDE, SULFUR AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF AMMONIA, MONO-PRIMARY-AMINES AND MIXTURES OF EITHER WITH SECONDARY AMINES WHEREIN NO MORE THAN ONE OF THE SUBSTITUENTS ATTACHED TO THE SECONDARY NITROGEN ATOM IS ATTACHED THERETO THROUGH AN AROMATIC CARBON ATOM. 